Chapter 2

Provide the name or chemical formula, as appropriate, for each of the following acids: (a) hydroiodic acid, (b) chloric acid, \((\mathbf{c})\) nitrous acid, \((\mathbf{d}) \mathrm{H}_{2} \mathrm{CO}_{3},(\mathbf{e}) \mathrm{HClO}_{4},(\mathbf{f}) \mathrm{CH}_{3} \mathrm{COOH} .\)

Give the name or chemical formula, as appropriate, for each of the following binary molecular substances: \((\mathbf{a}) \mathrm{SF}_{6},(\mathbf{b}) \mathrm{IF}_{5}\), (c) \(\mathrm{XeO}_{3},\) (d) dinitrogen tetroxide, (e) hydrogen cyanide, (f) tetraphosphorus hexasulfide.

The oxides of nitrogen are very important components in urban air pollution. Name each of the following compounds: (d) \(\mathrm{N}_{2} \mathrm{O}_{5},\), (a) \(\mathrm{N}_{2} \mathrm{O}\), (b) NO, (c) \(\mathrm{NO}_{2}\), \((\mathbf{e}) \mathrm{N}_{2} \mathrm{O}_{4}\).

Write the chemical formula for each substance mentioned in the following word descriptions (use the front inside cover to find the symbols for the elements you do not know). (a) Zinc carbonate can be heated to form zinc oxide and carbon dioxide. (b) On treatment with hydrofluoric acid, silicon dioxide forms silicon tetrafluoride and water. (c) Sulfur dioxide reacts with water to form sulfurous acid. \((\mathbf{d})\) The substance phosphorus trihydride, commonly called phosphine, is a toxic gas. (e) Perchloric acid reacts with cadmium to form cadmium(II) perchlorate. (f) Vanadium(III) bromide is a colored solid.

Assume that you encounter the following sentences in your reading. What is the chemical formula for each substance mentioned? (a) Sodium hydrogen carbonate is used as a deodorant. (b) Calcium hypochlorite is used in some bleaching solutions. (c) Hydrogen cyanide is a very poisonous gas. (d) Magnesium hydroxide is used as a cathartic. (e) Tin(II) fluoride has been used as a fluoride additive in toothpastes. (f) When cadmium sulfide is treated with sulfuric acid, fumes of hydrogen sulfide are given off.

(a) What is a hydrocarbon? (b) Pentane is the alkane with a chain of five carbon atoms. Write a structural formula for this compound and determine its molecular and empirical formulas.

(a) What is meant by the term isomer? (b) Among the four alkanes, ethane, propane, butane, and pentane, which is capable of existing in isomeric forms?

(a) What is a functional group? (b) What functional group characterizes an alcohol? (c) Write a structural formula for 1-pentanol, the alcohol derived from pentane by making a substitution on one of the carbon atoms.

Consider the following organic substances: ethylethanoate, ethylmethylether, hexanol, and propanone. (a) Which of these molecules contains three carbons? (b) Which of these molecules contain a \(\mathrm{C}=\mathrm{O}\) group?

Chloropropane is derived from propane by substituting \(\mathrm{Cl}\) for \(\mathrm{H}\) on one of the carbon atoms. (a) Draw the structural formulas for the two isomers of chloropropane. (b) Suggest names for these two compounds.

Draw the structural formulas for four structural isomers of \(\mathrm{C}_{4} \mathrm{H}_{9} \mathrm{Br} .\)

A cube of gold that is \(1.00 \mathrm{~cm}\) on a side has a mass of 19.3 g. A single gold atom has a mass of \(197.0 \mathrm{u} .(\mathbf{a})\) How many gold atoms are in the cube? (b) From the information given, estimate the diameter in \(\AA\) of a single gold atom. (c) What assumptions did you make in arriving at your answer for part (b)?

The diameter of a rubidium atom is \(495 \mathrm{pm}\) We will consider two different ways of placing the atoms on a surface. In arrangement \(\mathrm{A},\) all the atoms are lined up with one another to form a square grid. Arrangement B is called a close-packed arrangement because the atoms sit in the "depressions" formed by the previous row of atoms: (a) Using arrangement A, how many Rb atoms could be placed on a square surface that is \(1.0 \mathrm{~cm}\) on a side? (b) How many \(\mathrm{Rb}\) atoms could be placed on a square surface that is \(1.0 \mathrm{~cm}\) on a side, using arrangement B? (c) By what factor has the number of atoms on the surface increased in going to arrangement \(\mathrm{B}\) from arrangement A? If extended to three dimensions, which arrangement would lead to a greater density for Rb metal?

Identify the element represented by each of the following symbols and give the number of protons and neutrons in each: \((\mathbf{a}){ }_{5}^{11} \mathrm{X}(\mathbf{b}){ }_{33}^{75} \mathrm{X}(\mathbf{c}) \frac{86}{36} \mathrm{X}(\mathbf{d}){ }_{30}^{67} \mathrm{X}\).

The element argon has three naturally occurring isotopes, with \(18,20,\) and 22 neutrons in the nucleus, respectively. (a) Write the full chemical symbols for these three isotopes. (b) Describe the similarities and differences between the three kinds of atoms of argon.

The element chromium (Cr) consists of four naturally occurring isotopes with atomic masses 49.9460,51.9405,52.9407 and \(53.9389 \mathrm{u}\). The relative abundances of these four isotopes are \(4.3,83.8,9.5,\) and \(2.4 \%\), respectively. From these data, calculate the atomic weight of chromium.

Copper (Cu) consists of two naturally occurring isotopes with masses of 62.9296 and 64.9278 u. (a) How many protons and neutrons are in the nucleus of each isotope? Write the complete atomic symbol for each, showing the atomic number and mass number. (b) The average atomic mass of Cu is \(63.55 \mathrm{u}\). Calculate the abundance of each isotope.

Using a suitable reference such as the CRC Handbook of Chemistry and Physics or http://www.webelements.com, look up the following information for nickel: \((\mathbf{a})\) the number of known isotopes, \((\mathbf{b})\) the atomic masses (in \(\mathrm{u}),(\mathbf{c})\) the natural abundances of the five most abundant isotopes.

There are two different isotopes of bromine atoms. Under normal conditions, elemental bromine consists of \(\mathrm{Br}_{2}\) molecules, and the mass of a \(\mathrm{Br}_{2}\) molecule is the sum of the masses of the two atoms in the molecule. The mass spectrum of \(\mathrm{Br}_{2}\) consists of three peaks: $$ \begin{array}{lc} \hline \text { Mass (u) } & \text { Relative Size } \\ \hline 157.836 & 0.2569 \\ 159.834 & 0.4999 \\ 161.832 & 0.2431 \\ \hline \end{array} $$ (a) What is the origin of each peak (of what isotopes does each consist)? (b) What is the mass of each isotope? (c) Determine the average molecular mass of a \(\mathrm{Br}_{2}\) molecule. (d) Determine the average atomic mass of a bromine atom. (e) Calculate the abundances of the two isotopes.

From the following list of elements \(-\mathrm{Mg}, \mathrm{Li}, \mathrm{Tl}, \mathrm{Pb}, \mathrm{Se}, \mathrm{Cl}, \mathrm{Xe}, \mathrm{Si},\) C-pick the one that best fits each description. Use each element only once: \((\mathbf{a})\) an alkali metal, \((\mathbf{b})\) an alkaline earth metal, \((\mathbf{c})\) a noble gas, \((\mathbf{d})\) a halogen, \((\mathbf{e})\) a metalloidin group \(14,(\mathbf{f})\) a nonmetal listed in group \(14,(\mathbf{g})\) a metal that forms a \(3+\) ion, \((\mathbf{h})\) a nonmetal that forms a \(2-\) ion, \((\mathbf{i})\) an element that is used as radiation shielding.

The explosion of an atomic bomb releases many radioactive isotopes, including strontium-90. Considering the location of strontium in the periodic table, suggest a reason for the fact that this isotope is particularly dangerous for human health.

A U.S. 1-cent coin (a penny) has a diameter of \(19 \mathrm{~mm}\) and a thickness of \(1.5 \mathrm{~mm}\). Assume the coin is made of pure copper, whose density and approximate market price are \(8.9 \mathrm{~g} / \mathrm{cm}^{3}\) and \(\$ 2.40\) per pound, respectively. Calculate the value of the copper in the coin, assuming its thickness is uniform.

The U.S. Mint produces a dollar coin called the American Silver Eagle that is made of nearly pure silver. This coin has a diameter of \(41 \mathrm{~mm}\) and a thickness of \(2.5 \mathrm{~mm} .\) The density and approximate market price of silver are \(10.5 \mathrm{~g} / \mathrm{cm}^{3}\) and \(\$ 0.51\) per gram, respectively. Calculate the value of the silver in the coin, assuming its thickness is uniform.

Name each of the following chlorides. Assuming that the compounds are ionic, what charge is associated with the metallic element in each case? \((\mathbf{a}) \mathrm{AgCl},(\mathbf{b}) \mathrm{TiCl}_{4},(\mathbf{c}) \operatorname{Ir} C 1_{3},\) (d) \(\mathrm{LiCl}\).

Elements in the same group of the periodic table often form oxyanions with the same general formula. The anions are also named in a similar fashion. Based on these observations, suggest a chemical formula or name, as appropriate, for each of the following ions: \((\mathbf{a}) \mathrm{BrO}_{4}^{-},(\mathbf{b}) \mathrm{SeO}_{3}^{2-},(\mathbf{c})\) arsenate ion, (d) hydrogen tellurate ion.

Carbonic acid occurs in carbonated beverages. When allowed to react with lithium hydroxide, it produces lithium carbonate. Lithium carbonate is used to treat depression and bipolar disorder. Write chemical formulas for carbonic acid, lithium hydroxide, and lithium carbonate.

Give the chemical names of each of the following familiar compounds: \((\mathbf{a}) \mathrm{NaCl}(\) table salt \(),(\mathbf{b}) \mathrm{NaHCO}_{3}(\) baking soda \()\) (c) \(\mathrm{NaOCl}\) (in many bleaches), (d) \(\mathrm{NaOH}\) (caustic soda), (e) \(\left(\mathrm{NH}_{4}\right)_{2} \mathrm{CO}_{3}\) (smelling salts), \(,(\mathbf{f}) \mathrm{CaSO}_{4}\) (plaster of Paris).

Many familiar substances have common, unsystematic names. For each of the following, give the correct systematic name: (a) saltpeter, \(\mathrm{KNO}_{3} ;(\mathbf{b})\) soda ash, \(\mathrm{Na}_{2} \mathrm{CO}_{3} ;(\mathbf{c})\) lime, \(\mathrm{CaO} ;(\mathbf{d})\) muriatic acid, HCl; \((\mathbf{e})\) Epsom salts, \(\mathrm{MgSO}_{4} ;\) (f) milk of magnesia, \(\mathrm{Mg}(\mathrm{OH})_{2}\)

Because many ions and compounds have very similar names, there is great potential for confusing them. Write the correct chemical formulas to distinguish between (a) sodium carbonate and sodium bicarbonate, \((\mathbf{b})\) potassium peroxide and potassium oxide, \((\mathbf{c})\) calcium sulfide and calcium sulfate, \((\mathbf{d})\) manganese (II) oxide and manganese (III) oxide, (e) hydride ion and hydroxide ion, (f) magnesium nitride and magnesium nitrite, \((\mathbf{g})\) silver nitrate and silver nitrite, \((\mathbf{h})\) cuprous oxide and cupric oxide.

In what part of the atom does the strong nuclear force operate?